March 29, 2012

Engine: Cummins QSB6.7 480hp

Cummins presented the new QSB6.7 at the latest 2012 Miami boat show.  This new engine offers better performance, improved sociability, and improved operations over Cummins beloved QSB5.9 model, all without sacrificing fuel economy. The initial launch of the QSB6.7 will provide both commercial and recreational ratings from 380 up to 480 hp.  The Cummins QSB6.7 provides more torque, which means better acceleration and maintained speed through turns. A pair of QSB5.9 480 hp engines installed in a pod-driven 44 feet express cruiser test boat accelerated the boat to 20 mph in 14 seconds, while the same boat powered by QSB6.7 480 hp engines accelerated to 20 mph in just 8 seconds, with little change to the legendary QSB fuel economy. The QSB6.7 also employs a new fuel calibration strategy: Unlike most marine engines, the QSB6.7 is calibrated for optimal fuel economy at cruising speeds, where the engine is most often used, rather than at wide-open throttle.  The QSB6.7 is sociably improved, capable of meeting EPA Tier 3 emissions standards. This new engine offers exceptionally low cold-start smoke levels, and significant sound reduction at cruise and rated speeds compared to the QSB5.9.  Operationally the QSB6.7 has improved with loads of new features. The standard fuel system is compatible with low lubricity fuels. With the use of Ultra Low Sulfur Diesel this engine offers extended oil change intervals, providing fewer oil changes and more time on the water. Another notable feature of the QSB6.7 is the PTO capability. The power steering and hydraulic pumps are gear driven, providing a substantial reliability improvement over belt-driven systems. For accessories that must be belt driven, such as a clutched Freon compressor, there is an additional belt driven PTO location above the seawater pump.